Electric throttle control system



March 30, 1943. O PUTT ELECTRIC THROTTLE CONTROL SYSTEM Filed Oct. 17,1941 Fatentecl Mar. 3Q, 3943 PATENT OFFICE OTTLE CONTROL SYSTEM 6Claims.

This invention relates to throttle control systems for internalcombustion engine; and in particular, multi-engined aircraft, and hasfor its first objective the remote control of carburetor throttles byelectrical means and spring tension.

Another object is to provide means whereby the various throttles of thevarious motors of a bombing plane are closed by electro-magnetic actionand opened by spring tension, in a manner and for the purposehereinafter described.

A further object is to provide operative means and apparatus, soconnected to an electrical circuit, that a carburetor throttle, or aplurality of carburetor throttles, will be fully opened and held open byspring tension or the forces of gravity or inertia, or by both springtension and gravity or inertia, in case of disruption of said circuit orcircuits, or loss of electrical power.

I attain these and other advantages and objects of my invention by themechanism illustrated in the accompanying drawingyin which- Figure 1 isa view partly in section and partly in side elevation of a carburetorwith its throttlearm connected to its solenoid plunger in thedeenergized position and showing th throttle-valve T in the full openposition;

Fig.2 is a diagrammatic view of the circuit arrangement, showingconnections'to the various controls and the battery; and also showingthe various carburetor throttle arms connected to their respectivesolenoid plungers in the ener-- gized position and with all throttlevalves in their closed position.

,It has been the practice of aviation companies to arrange the throttlcontrol of their multimotored bombers and transport planes to functionin the same manner that is employed on automobile and trucks; that is,the throttle is opened by manual effort and closed either by manualeffort or spring tension.

In some cases this throttle control was effected through the medium of asystem of rocker-shafts, bell-cranks and levers, similar to thatemployed on automobiles; while in recent practice, an elabrate andexpensive hydraulic system is being employed, but in both cases thethrottle is opened by manual effort or forces liberated by manual effortand closed by spring tension", or the same force that opened it.

Now assume that a two or four-motor bomber, with a throttle controlsystem arranged to operate as above, was making a power dive toward someobjective protected by anti-aircraft weapons, and a piece of shrapnelshould sever or bend or otherwise damage the mechanical controlshafting, cranks or levers, extending from the control cabin out to themotors on the wings, it might render one or more motors useless. In caseof a hydraulic system, the rupture or puncture of the relatively longpipes or tubes carrying the fluid would immediately affect two or moremotors, because fluid pressure would no longer be available to maintainthrottle control or an open throttle. Thus, with either of these systemsa condition would exist wherein the chance of motor failure would beincreased at the most critical period, and contribute to or be thedirect cause of the loss of the ship and its crew, because of the pilotsinability to pull out of the-dive through loss of power.

In contradistinction to the above described systern of throttle control,my electric system functions in exactly the reverse manner, in that Iprovide means and power to force the throttles closed, or to theiridling position, and provide spring tension and inertia to pull themopen. Instead of shafting, rods or tubing extending from the controlcabin out to the carburetor, I employ suitable electric wire or cable,which may be armored if desired, and which may be run in any desiredmanner or angle and requiring less space.

If the throttles are to be opened slightly, current is reducedproportionately and if 1111 .throttie is desired, current is cut oilentirely, hence it a bomber is equipped with my system of control and apiece of shrapnel should sever a wire leading to any of the solenoids ateach carburetor, that throttle would assume a full open position, or ifit was already open (which would be or might be the case during a powerdive) then the severance of this wire or wires would have no effect onthe motor it controlled. If the severance of this or any other controlwire should cause a short circuit, then the fuses in those circuitswould be blown and no harm result. Thus, the pilot would have that onechance of pulling out of the dive with full power and getting away, thathe would not havewith either of the other systems ofcontrolhereinbe'fore described.

With one or all motors on full throttle, due to severance of one or morecontrol wires or circuits, or the destruction or injury of the batteryor other source of power, the pilot could reduce his speed by cuttingthe magneto ignition to two or all motors to eiiect a safe landingspeed.

Referring to the drawing in which like characters of reference designatelike parts in each of the views, Figure 1 illustrates a carburetor I,partly in section, showing a throttle valve T, and valve arm 3. Thelatter is fulcrumed to the plunger rod 2 of the solenoid S. The lowerhollow cylindrical extension i l of solenoid S is outside the magneticfield and is suitably fulcrumed at l. It is grounded as shown in Figs. 1and 2. One end of a spring is suitably attached to the valve-arm 3 andthe other end secured to the solenoid as shown, or to any other suitablefixed point. The solenoid is shown in Fig. 1 in its deenergized positionwith the throttle valve wide open. As shown, the solenoid is disposed inan upwardly slanting position, whereby gravity will tend to pull theplunger rod l2 downwardly and tend to open the throttle valve T. Thesolenoid S may be of any desired construction, but it is designed sothat one end of its iron plunger 12 will normally rest just inside ofthe magnetic field of the coil Hi. When the magnetic coil i3 isenergized, the plunger i2 will be drawn into the central portion of thecoil against the tension of the spring 5 to close the throttle valve T,as shown in Fig. 2. One end of the solenoid winding I3 is grounded onthe tube l l, while the winding and the other end thereof i5 isinsulated from ground, in the conventional manner.

When the plunger is drawn into the solenoid when same is energized, asuction effect is created below the lower extremity of the plunger andthis suction is relieved by the air that is drawn in through the upperopen end of the tube M, past the plunger and into the lower internalextremity of the tube I4, thus preventing a slamming action of the valveT and providing a cushioning effect.

When solenoid is de-energized and the spring 5 pulls the plunger I2 backtoward its lower position, the trapped air within the lower portion ofthe tube I4 is forced upward past the plunger l2 and out through theopen end of the tube I4, thus providing for a cushioning effect in thisdirection of plunger movement. Thus, the action of the plunger is smoothand shockless in either direction of movement. The rapidity of movementof the plunger in either direction is predetermined by the amount ordegree of clearance between the plunger and the tube i l. The less thisclearance is, the greater the cushion effect and the slower will be themovement of the plunger. Increasing the clearance permits the air'toenter or escape with greater rapidity thus increasing the rapidity ofplunger movement under the influence of electro-magnetic action orspring tension.

The diagrammatic view of the electrical circuits and associated deviceselectrically connected therewith is clearly indicated in Fig. 2. Theelectrical circuit is as follows:

Referring to Fig. 2, starting at the battery 6, one pole of the batteryis preferably grounded. The other pole is connected to a suitable switchcontact, so that when contact arm l of said switch is in the solid lineposition shown in Fig. 2, current will flow through said arm '3, thence.to one end of the resistance 8, thence through a rheostat oraccelerator control arm 9, thence to one end of each of the adjustablecompensating resistance units RI, R2, R3 and R 5, as shown, thence intoeach of the contact arms Hi, We, lfib and H10, thence through the fusesH, No, lib and lie to each of the solenoid terminal Wires l5, l5a, b andH30. Each of said solenoids is thus energized, causing their respectiveplungers to be drawn into the said solenoids to force each of thecarburetor throttle valves to their idling or closed position,substantially as shown. All of the throttle valves are moved synor Or)chronously by means of the accelerator control arm 9 when the controlsRI, R2, R3 and Rd are in their normal position as shown in the drawing(Fig.2).

Due to voltage drop in the different length circuits to the solenoids,the compensating re sistances or rheostats Rl, R2, R3, and R4 areadjusted to provide identical current input to each solenoid so thattheir field intensity will be the same. Each spring 5, 5a, 5b and 50should be adjusted to an equal tension.

It will be observed that the throttle or accelerator resistance 8 is cutout" of the circuit at full closed throttle position, because thecontact arm 9 is in contact with the same end of a resistance 5 that isconnected direct to battery 6. Hence the full maximum current will flowthrough the contact arm 9 to each of the compensating resistances andthence to the several solenoid windings and to ground, thus holding theseveral carburetor throttles in their off or idling position; but if theaccelerator arm 9 is depressed, more and more resistance will beintroduced into the circuit which will cause the field intensity" of therespective solenoids to decrease proportionately and as this factordecreases, the springs 5, 5a, 5b and 50 will pull the throttle valvesTl, T2, T3 and T4 open proportionately, until, if the arm 9 is depressedto the dotted line position shown, the battery will be disconnected andall solenoids de-energized, thus permitting the springs 5, 5a. 5b and 50to force all the said throttle valves to the full open position shown inFig. l, by means of the above-described spring tension and gravitationaleffect on the plunger.

A sudden release of the accelerator-arm 9 will cause it to return to thesolid line position shown. by means of the spring l6 or otherwise,thereby increasing the current volume to each of the said solenoids, theaction of which would instantly force all of the throttle valves to theclosed or idling position shown in Fig. 2. If the accelertor arm 9 isreleased gradually, then the solenoids would be energized gradually andthe throttle valves would be moved in unison gradually to- Ward theidling position and thus gradually reducing the speed of all motorsproportionately.

Each of the compensating rheostats RI R2, R3, and R5 are provided withisolated contacts ll, lla, Nb, and He, respectively whichare allconnected together in parallel to the wire l8 which leads to and isconnected with the discharge side of the battery & specifically asshown. Any or all of the rheostat contact arms Ill, 10a, lllb, and lilomay be moved to the extreme right out of contact with their respectiveresistances and into contact with the points H, Ha, ill) and lierespectively, thus permitting full current volume to flow directly totheir respective solenoids, the action of which would energize same andcause the several throttles to be forced to their idling positionregardless of the position of the accelerator control arm 9.

Now, assume that the pilot desired to idle the two motors on the leftwing and accelerate the two motors on the right wing he would then turnrheostats R! and R2 to the extreme right, which action would fullyenergize the solenoids on the left wing carburetor and force theirthrottles to the idling position. At the same time he would depress theaccelerator arm 9 the required degree to accelerate the two right wingmotors, after which he would release the arm 9 to the normal positionindicated in Fig. 2, and re-set the rheostats R! and R2. To acceleratethe left wing motors and idle the right wing motors, he would turnrheostats R3 and Rd to the extreme right position and at the same timedepress the accelerator arm 9 as before.

Any one or more of the motors may be idled and the others accelerated asdesired by the proper manipulation of the rheostats RI, R2, R3

and R4 and the throttle control arm 9 as above ulated as desired tofacilitate taxiing or maneuverability on the ground or in the air andafter attaining the desired altitude, flight at full throttie with nocurrent'consumption as respects the solenoids. Only during the warmingup, idling, or part throttle operation is current consumed. The locationof the solenoids close to the motors, obviates any chance of plungerssticking due to 4 moisture or ice, and all other equipment such as thecompensating rheostats, accelerator control, fuses, switch and batteryare located in the control cabin where they may be made easilyaccessi-ble.

It is to be noted, with the solenoids in the position shown and assumingthat this view is toward the nose of the plane or direction of travel,that when pulling out of a dive, executing sharp turns, rolls or loops,requiring full throttle, the

forces of inertia act on the plungers in the same direction as that ofthe spring 5 to open the throttle and hold it open until less power isrequired.

The tension of this spring should be ample to insure the return of theplunger to its normal position when the solenoid is de-energized.

The cost of my electric throttle control system would be no more andprobably much less than the cost of the hydraulic system now in use andthe saving of the crew and one bombing plane through the safety factorsincorporated in my invention, would pay for hundreds of these controlsystems.

What I claim is:

1. In an electriothrottle control system for internal combustionengines, the combination with a plurality of internal combustionengines, of a master control element, throttle valves for thecarburetors of each of said engines, spring means operatively connectedwith each of said valves and normally holding the valves in openposition, a solenoid for each of the valves, each solenoid having itsplunger rod operatively connected with the respective valve and arrangedto close same, and electric means connected with each of the aforesaidsolenoids for independently operating same to permit of independentcontrol of the closing of each of the valves by the solenoid plunger,and for combined and simultaneous control of all valves in unison bymeans of the master control element.

2. In an electric throttle control system for internal combustionengines, the combination with a plurality of internal combustion enginesof the ,master control element throttle valves for the carburetors ofsaid engines, independent spring means operatively connected with eachof said valves and normally holding the valves in open position, asolenoid for and operatively connected with each valve and arranged toclose same, and electric means connected with each of the aforesaidsolenoids for independently operating same to permit of independentremote control of each of the said valves by the solenoid plunger andelectrically controlled means for combined and simultaneous control ofall valves synchronously by means of the master control element, each ofthesolenoids having a hollow cylindrical extension for the plunger ofthe solenoid to protect same from ice and'snow, and act as a guide forthe said plunger.

3. In an electric throttle control system for internal combustionengines, the combination with a plurality of internal combustion enginesof throttle valves for the carburetors of said engines, independentspring means operatively connected with each of said valves and normallyholding the valves in open position, a solenoid for and operativelyconnected with each valve and arranged to close'same, and electric meansconnected with each of the aforesaid solenoids for independentlyoperating same to permit of independent remote control of each of thesaid valves by the solenoid plunger, a rheostat for combined andsimultaneous control of all valves synchronously, said solenoids beingdisposed in a position whereby gravity will tend to pull the plungersdownwardly and thereby tend to open the proper valves, whereby thethrottle control valve will normally be held in open position.

4. In an electric throttle control system for internal combustionengines, the combination with a plurality of internal combustion enginesof a master control element, throttle valves for the .carburetors ofsaid engines, independent spring means operatively connected with eachof said valves and normally holding the valves in open position, asolenoid for and operatively connected with each valve and arranged toclose same, and electric means connected with each of the aforesaidsolenoids for independently operating same to permit of independentremote control of each of the said valves by the solenoid, and forcombined and simultaneous control of all valves in unison by means ofthe aforesaid master control element, plungers for forcing the throttlesi to idling position by means of electric power and causing them to opengradually by reducing said power or to open instantly upon disruption ofsaid electric power.

5. In an electric throttle control system for internal combustionengines, the combination with a plurality of internal combustion enginespower, and causing them to open gradually by reducing said power or toopen instantly upon dismption of said electric power, and rheostats forregulating current input to each of the solenoids, whereby they willcause the throttle valve'of all the engines to move in unison towardidlingposition when the solenoids are energized.

6,. In an electric throttle control system for kr ll power and causingthem to open gradually by reducing said power or to open instantly upondisruption of said electric power, rheostats for regulating currentinput to each of the solenoids,

whereby they will cause the throttle valve 01' all the engines to movein unison toward the idling position when the solenoids are energized,each of they solenoids having a hollow cylindrical extension tor theplunger of the solenoids to protect same from ice and snow in highaltitudes, and act as a guide for same.

, HARLIE O. PUTT.

